


Experiments on A Tuesday

by SherlocksSister



Series: Tuesdays and Thursdays [1]
Category: Sherlock (TV)
Genre: First Time, For Science!, Friends to Lovers, John is a Very Good Doctor, Lisping Sherlock, M/M, Mild Hurt/Comfort, Post S4, Sherlock Holmes Experiments on John Watson, Sherlock is a Good Parent, sherlock's hands
Language: English
Status: Completed
Published: 2017-03-26
Updated: 2017-03-31
Packaged: 2018-10-11 00:18:40
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 6
Words: 8,817
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10450761
Author URL: https://archiveofourown.org/users/SherlocksSister/pseuds/SherlocksSister
Summary: It is the week after John and Rosie move back to 221b and Sherlock is conducting an experiment that ends with him getting hurt. Over the next 5 Tuesdays this pattern is repeated until John works out what is going on and designs an experiment of his own. There are 5 chapters, 1 for each experiment.Written for the March Sherlock Challenge on Tumblr for the prompt "Experiment Gone Wrong."Sherlock Challenge





	1. Tuesday, 1 week after John returns to 221b

**Author's Note:**

  * For [herasmom](https://archiveofourown.org/users/herasmom/gifts).



> This is for Herasmom who always leaves the loveliest comments, not just on mine, but on a lot of writer's fics. We are nothing without the support of our readers and it is much appreciated. As always, huge thanks to my beta Breath4Soul.

Rosie squirms down from John’s lap to play with her Iggle Piggle plushie and he carries on regaling Sherlock in the kitchen from his perch on the couch. It won’t matter if her bedtime is ten minutes late.

“So, then she leaned over and said, ‘Well,  _ Doctor _ Watson, being a surgeon doesn’t exactly require you to be familiar with the finer points of child development’ and  _ I _ said, ‘no, but being a Public Health Nurse doesn’t qualify  _ you _ to ride roughshod over the opinions of a parent, and my point is simply that-”

“Um, John, I-”

“And what  _ really  _ gets up my nose, is that she was all, ‘I didn't say she  _ had  _ to have female company, I was merely inquiring as to whether there was a consistent-”

“John, I seem to have slightly miscalculated and it may be prudent to-”

_ Bang _ !

John leaps up from his chair and spins to face the kitchen. 

A small puff of smoke is gently wafting up from Sherlock’s right eyebrow.

“Jesus, Sherlock, not again.” John wanders into the kitchen. His eyes automatically go to the ceiling, waiting for the smoke detector to go off and assessing the damage. A fireball always leaves a mark on the ceiling. It’s only when his eyes drop to Sherlock’s face that he realises that Sherlock’s right eyebrow is, in fact, ever so slightly still alight, embers dancing amongst the densest hairs in the middle.

“Fuck! You’re on fire.” He leaps forward, grabs the nearest thing he can - Sherlock’s suit jacket hung over the back of the kitchen chair - and presses it to Sherlock’s face.

The smothered Sherlock mumbles something unintelligible and bats at John with his hands, trying to push the jacket away. It would seem John is also stopping his flow of oxygen. Later, no-one can say for sure if that was unintentional.

Standing back to assess the damage, John crosses his arms and sighs. Sherlock is wiggling his eyebrows up and down, then frowns when he realises that the right one is sore. He heads into the bathroom to assess the damage. John saunters in after him, and from behind his shoulder, tries not to laugh. The eyebrow is properly singed with a distinct stripe burnt from the middle.

“It’s hurts, John,” states a mildly accusative Sherlock, as if John had been the idiot that has set him alight.

“I’m not surprised, you daft bugger. What were you doing in there anyway?” He reaches into the cupboard under the sink for his first aid pack and pulls out a cooling aloe vera burn cream. 

“I was mixing ethylmenatriox and panthic acid to see how long it takes to produce an exothermic reaction. I have a theory that it may be connected to how Sidney cleared the evidence from the crime scene. However, I suspect that the panthic acid was of a more concentrated level than I calculated. I wasn’t anticipating a reaction of that proportion. My apologies if I frightened Rosie.”

John sticks out his head and peers at his daughter who is still playing happily with her toys. He wonders if maybe the Public Health Nurse had had a point.

“She doesn’t seem to have even noticed.” He smiles, washing his hands. “Here, stand still.”

He smooths the burn cream over Sherlock’s eyebrow and gives his cheek a gentle pat.

“Put that on for the next couple of days, it’ll soon heal. In the meantime, you will just have to accept your beauty being reduced to that of us mere mortals until the hair grows back.” He heads back into the living room to Rosie.

  
Sherlock frowns at his retreating back, confused by the use of the word ‘beauty’ but stops because it makes his eyebrow hurt. He returns to to examining the damage in the mirror. Later, he spends two hours setting up a colour-coded spreadsheet in which to record the findings of his experiment. 


	2. The Following Tuesday

**Summary for the Chapter:**

> A week later, and Sherlock is licking things he shouldn't.

Lestrade rubs his chin, peering alternately at his phone and then down at Sherlock. Each pass between the phone and Sherlock gets shorter and shorter. 

“Well, can you tell us something or not?”

Slowly, John lowers himself down next to Sherlock and the female corpse laid out on the beige carpet. They have already been there for twenty minutes, usually long enough for Sherlock to finish examining the body, insult everyone in the room and be in a cab heading home. 

“Sherlock?”

“Hmmmmm?”

“Is everything … alright?”

“Of course not, John. We are in the home of the former Chancellor of the Exchequer’s ex-wife. She is dead and, more to the point,  _ doesn’t have her shoes on. _ How could it possibly be alright?”

John just stands up again and shrugs at Greg, who consults his phone once more. It chimes as he looks at it. With a sigh, Greg reads the incoming text and pales.

“Shit. The Chief Super’s on her way.  _ Shit _ . C’mon Sherlock, give me something. Please. Anything.”

The initial check of the body has revealed nothing. No wound or mark out of the ordinary at all. As Sherlock crawls around on the floor, he lifts the woman’s hair once more and peers closely. In one swift move he is back down by her feet again, hands hovering in the air over the stockinged heels. Scrambling once again to the outflung right arm, Sherlock lies flat on his stomach and gets within millimeters of the gold bangle on the woman’s wrist. 

The other officers have completed their sweep of the three-bedroomed flat and found nothing of note. A small crowd is gathering around the oblivious Sherlock as he once again crawls around the woman’s body and examines her upturned left ear with his pocket magnifier.

He glances up at John, standing, arms folded, at the woman’s head. John surveys the assembled crowd and slowly descends once more to join Sherlock on the ground. 

“John, I have one idea but…” Sherlock keeps his voice low to try to have some privacy from their audience.

“What?” John frowns at Sherlock. He has never seen him exhibit such reticence before at a crime scene.

“It’s just, I need to … to be sure, I mean, I need to do…”

“Do what?” John hisses at Sherlock. “Whatever you need to do, do it. I think Greg’s about to have a heart attack and some big wig is on her way and you know that almost never ends well for us.”

Sherlock grins at John; a sharp, mischievous smile. “I need to do an experiment, John.”

The circle of onlookers leans in slightly as Sherlock folds himself up in such a way that he can reach the woman’s left ear. He sniffs her ear, her shoulder and her hair. John realises what Sherlock is going to do at the very moment he sees the man rub his bottom lip along the skin behind the dead woman’s ear, then stick out his tongue and take a long, broad lick. 

An exhalation of “urrrggghhh” from everyone in the room is instantly followed by the police breaking their formation, revulsion clear on everyone’s face.

“Jesus Christ, Sherlock!” John cannot believe what he has just seen. “What the actual fuck are you doing?”

“Methylbarbansulphinate, John. I thought I could smell it but I had to be sure. It was mixed in with the perfume so I couldn’t be sure from scent alone. It has a distinctive sweet taste.”

A delighted Sherlock uncurls from the floor, straightening his suit jacket and dusting off his hands.

“She was poisoned, Lestrade. It was mixed into her perfume and then absorbed into the bloodstream via the thin skin of the neck, under the ear and the soles of her feet. It was her ex-husband, of course, jealous of her new relationship.”

He strides off towards the door, uncaring or oblivious to, the head shaking and stunned silence at his actions. John chases after him.

“Sherlock you can’t go around licking dead bodies. It’s just not...not…” He trails off, ‘good’ not coming even remotely close to what he is trying to say.

Back in Baker Street, Sherlock heads straight up the stairs while John calls into Mrs. Hudson to pick up Rosie. He takes her straight up to their room to change her into her pajamas when he hears what sounds like Sherlock calling. He and his daughter descend the stairs when he hears the peculiar sound again.

“Thawn”

“Sherlock, what’s the-” He reaches the bottom of the stairs and turns into the kitchen, Rosie wriggling to get out of his arms. Sherlock, also in his pajamas, is sat at the table, head in his hands.

“Thawn, I dthon’t fweel thery wewl.”

Sherlock raises his head to reveal two ballooning lips, eyes so puffy they are almost closed and his distended tongue lolling slightly over his bottom lip.

“Oh my God, you’re a disaster! You must have had an allergic reaction and you said that stuff was poisonous.” John runs to the bathroom for his first aid kit before realising he probably needs something more significant and gallops upstairs to get his first responder treatment bag.

Back in the kitchen he grabs a glass of water and two anti-histamine tablets and hands them to Sherlock who struggles to take them as his tongue will not fit into his mouth. He roots around in  his bag until he finds the activated charcoal tablets at the bottom.

“We don’t make people vomit anymore. See if you can take one of these and it may save us from a trip to A and E.” Sherlock makes pitiful eyes at him; the dark black tablet is so large it looks like it could fell a horse. Somehow, with copious dribbling and encouragement, Sherlock manages to swallow the tablet. 

John checks his tongue again to establish if it is still swelling. He runs his fingers around Sherlock’s neck and under his chin looking for any signs of a rash. Sherlock’s bottom lip is particularly puffy.

After half an hour of close observations with an Epi-pen waiting on the counter, John is satisfied that the anti-histamines have been sufficient and the swelling is receding. Sherlock is lying with his cheek on the cool tiles of the table top. John rubs his bottom lip soothingly with an ice cube.

“Are you starting to feel any better?”

Sherlock nods and tries, unsuccessfully, to speak. He licks his bottom lip and tries again, “Yeths” and frowns at the continuing impediment. “‘M thorry Jthawn.” 

John shakes his head affectionately and draws a delicate thumb over the bow of Sherlock’s poor top lip. “I’m just glad I am not standing in A and E while you have your stomach pumped. At least you solved the murder. I expect the Prime Minister will be wanting another word. Keep rubbing the ice over your lips, it’ll help.” He strokes a soothing hand over Sherlock’s shoulder. “At least we can see your pretty eyes again.” and he wanders off to pick Rosie up from the middle of her toys. 

Sherlock blinks carefully, smiles as much as the swelling will allow, which is not very much at all, and watches them from his sideways viewpoint on the kitchen table.

  
When he is feeling much better four hours later, aided by a small nap, Sherlock spends a happy hour with his laptop and a cup of tea adding to his spreadsheet.


	3. The Tuesday after that

**Summary for the Chapter:**

> Sherlock gets revenge and John gets worried.

**Notes for the Chapter:**

> just a small trigger warning for knives and blood.

John leans over the sofa so that Sherlock can kiss Rosie goodnight. The little smooch he does on her cheek tickles and she giggles as John carries her up to bed. Three and a half repetitions of ‘Twinkle Twinkle Little Star’ later, he creeps back down the stairs.

“Nice cup of...Oh, what’s going on here, then?” He stands in the doorway to the darkened living room, Sherlock having closed all the curtains and turned off the lights.

“An experiment, John, for the Belluci case. I need to test how accurately a knife thrower can aim at a distance of 10 feet and in 85 per cent darkness.” Sherlock arranges six huge cork tiles propped against the wall behind the sofa. “I thought this might add an element of fun.” He grins, unrolling a life-size paper cut-out figure and pinning it to the tiles.

“Sounds fun. Can I have a go?”

“Of course. Do you wish to use your own throwing knifes or will mine suffice?”

“My own, what the-? No, Sherlock, I do not have my own set of throwing knives.”

“No? Oh. Even after all this time, you still manage to surprise me.”

John just shakes his head and watches in the gloom as Sherlock carefully unrolls a set of steel knives. Each one is seven inches long and their handles are moulded from the same steel as the blade. It is only as he glances at the target, estimating the distance, that he realises he is looking at a life-sized replica of Mycroft.

“Nice target. Still working on some Sherrinford issues?”

“One needs all the therapy one can get with my brother and his decision making,” Sherlock agrees. “I do hope he is watching.”

They stand as close to the mantelpiece as possible and take turns throwing the knives, aiming for Mycroft’s head. Each time he throws, Sherlock’s dressing gown flows behind him dramatically. 

It takes John a few attempts to warm up and then his shot becomes increasingly accurate, despite the dim light. They thoroughly enjoy themselves, trying to out throw each other. John watches Sherlock remove his last three knives, as he thinks that other blokes just play darts. 

John makes three consecutive throws that land right between Mycroft’s eyes. Sherlock’s own throws are less consistent but each one lands within the broader target of Mycroft’s head. It is only after an hour of egging each other on, commiserating over poor throws and John’s victory dance, that he realises he has no idea what hypothesis they were meant to be testing.

“Tea?” John suggests when Sherlock finally concedes defeat. John switches on the light as he heads to the kitchen.

He has one hand on the kettle when he hears the sharp cry of pain from Sherlock. He bolts the few feet separating them to see Sherlock stood at the desk, holding his left hand up as blood pours down the back of his fingers.

“Fuck, Sherlock!” John sprints back to the kitchen and grabs a clean tea towel from the drawer. He wraps it around Sherlock’s hand and squeezes hard. Simultaneously, he  wraps his other hand over Sherlock’s own, where it is holding his wrist up, and raises it higher to reduce the blood flow. They are standing chest to chest and John can see the embarrassment in Sherlock’s face; his reluctance to look John in the eye.

“What happened?” He asks quietly, not wanting to make any more of a fuss than he already is. 

“I was putting the knife away and it slipped, fell down and hit off the knuckles of the other hand.” Sherlock winces.

“Let’s have a look, shall we? See what bit of you actually got cut?”

John lowers their hands and gingerly unwraps the tea towel. He breathes out in relief when he sees Sherlock has grazed the knuckles of three fingers but hasn’t done any serious damage. The bleeding has already eased up.

“You had me properly worried there; I thought those talented hands were seriously hurt. God, Sherlock, what if you had cut a tendon, or the knife had gone all the way through?” John carefully turns the hand over and examines Sherlock’s palm, drawing his finger over the heel of Sherlock’s thumb, then the crease going across the middle. “How would that affect your violin playing and your lock-picking? You really need to be more careful, Sherlock.” 

Gently, he stretches out each of the long fingers, not enough to hurt but enough to make sure they have feeling and movement. He bends his head and carefully places a small kiss on the tip of Sherlock’s index finger. “All better,” he breathes. “I’ll get the bandages.”

It takes just fifteen minutes for John to clean and dress the damaged knuckles. When he examines them closely, he can see that really it was the very top layers of skin that had been removed, that the blade must be very sharp to have made such a clean cut. He is shocked at the damage Sherlock has done to those expressive hands.

John makes tea and watches Sherlock from the kitchen. There is something nagging at the back of his head; the knowledge that something isn’t quite right here. He sits down on the sofa next to Sherlock and they quietly watch telly for a while until Sherlock drags out his laptop and starts flying over the keys with just his right hand.

John is too distracted by his own thoughts to pay attention to what Sherlock is typing, or to notice his own sidelong glances at John.

The next morning, while Sherlock visits a circus museum for further research on the Belluci case, John phones Mycroft.

“I’m a bit worried about Sherlock.”

“How so?”

“He’s become a bit … careless. With his experiments. Seems to be getting hurt a lot more than usual.”

“Really?” drones Mycroft. “How on earth can you tell? He is perpetually blowing something up or dismembering it in the kitchen. Have we already forgotten the exploding lung incident of 2016?”

“Yeah, no. That’s true, although, he doesn’t actually set fire to the place as often as people like to pretend. It’s just that he’s not damaging  _ things _ . He’s damaging himself.”

There is a quiet moment on the end of the line. “What are you suggesting, John?” 

John is momentarily distracted by the fact that Mycroft is now addressing him as ‘John’. In the past, Mycroft would always address him as ‘Dr. Watson’ when they discussed Sherlock’s wellbeing. It seems Mycroft has taken Sherlock’s insistence that he is family to heart.

“Oh, I don’t know. I was wondering if maybe…” John sighs.

“Maybe?” Mycroft prompts.

John takes a deep breath. “I was wondering if maybe there has been long-term damage. You know, from all the drugs? It could have caused nerve damage, affected his co-ordination”

Or, possibly, the beating, no-one says out loud.

Or the psychological trauma of being lied to about your dangerous sister for more than thirty years no-one else says.

“I suppose it is always a possibility.” Mycroft agrees. “Although you would know more about that than I. What do you suggest?”

“Nothing, really. Look, it might be nothing. I’ll just keep an eye on him and if I think we need to get him checked out. We can work together on persuading him to see a specialist.”

“Agreed. Keep me informed. Now, I must take your leave, I have a rather important meeting to attend. Goodbye, John.”

  
John hangs up, not feeling at all reassured.


	4. 4 Weeks After This Whole Nonsense Started

**Summary for the Chapter:**

> Sherlock forgets his shirt and John remembers he's a scientist.

As he sits in his chair, gratefully sipping tea, John can’t hear exactly what Sherlock is saying, but the splashes, giggles and rumblings of laughter tell him that Sherlock and Rosie are having fun.

They have fallen into a routine of Sherlock giving Rosie her bath over the last two weeks. It works well, especially if John has been in the surgery that day. He gets the chance to eat in peace and relax with a cup of tea. Then, Sherlock will hand a towel-wrapped Rosie over to him for pajamas, drink and a story before John takes her upstairs and tucks her into her cot. 

When Rosie was born, Sherlock had undertaken a detailed analysis of a considerable number of child development studies, some having been conducted over more than forty years. He had distilled the key findings and solemnly handed them to John and Mary. John grimaces as he recalls Mary’s disdain for the page. “As if you can raise a child by bullet points, John,” she had snarked, throwing the sheet of paper in the bin.

When Mary had disappeared on her attempt to evade Ajay, Sherlock had become much more involved in Rosie’s day-to-day care. He had used these bullet-pointed findings to insist on two things; routine, especially at bedtime, and that they read to Rosie at every possible opportunity. He also had very strong feelings on vaccinations.

It also transpired, once Mary had done her vanishing act, that John was inclined to agree with Sherlock. He, too, appreciated routines in his parenting and nothing made him happier than sitting with Rosie on his lap as he attempted to read her a book and she did her best to chew it. 

When John moved back into 221b, they had discussed Sherlock’s involvement in Rosie’s life. John had not wanted to presume but was delighted, and quite surprised, when Sherlock jumped at the opportunity to act in a parental role for Rosie. They had negotiated some ground rules and taken it from there. There have been difficult days; the incident with the pureed beetroot... but, on the whole, it seems to be working very well. One thing is clear; Rosie adores Sherlock and the feeling seems to be mutual.

John’s musings are interrupted by Sherlock depositing a damp Rosie in his lap for dressing before striding away into the kitchen. John only gets half way through reading, ‘That’s Not my Fire Engine’, before Rosie falls asleep in his arms. She stays sound asleep as he lifts her into her cot. 

John heads for the kitchen, intent on another cuppa. He is surprised to see Sherlock working at the kitchen table, peering into his microscope. More surprisingly, Sherlock is stripped naked to the waist. He seems utterly engrossed in what he is doing and John glances briefly over those broad shoulders, no longer gaunt the way they had been after his release from hospital. Instead, they are returned to their natural slim, but strong, glory.

Glory? John frowns to himself at his own choice of phrase but pushes the thought away and takes a closer look at Sherlock’s chest and arms while he steps around the table to the kettle. When Sherlock first came home from hospital, he had been so weak that John had needed to help him shower. He has seen Sherlock in a state of near nakedness more than once, yet he doesn’t seem to be able to take his eyes off the man now. Thankfully, Sherlock is oblivious to his staring.

John risks a sideways peer as he waits for the kettle to boil. This time, he has a long look at the scars criss-crossing Sherlock’s back. The sight leaves him reeling, as if he himself has been struck; they are long, were obviously deep and there are just so many of them. He is lost for a moment, imagining how much pain Sherlock must have been in when they were inflicted. Anger rises in his chest at the scum that did this, immediately doused by a wave of shame. He is no better than those who left Sherlock with these scars but he is determined to spend the rest of his life trying to make it up to him.

Unconsciously, he reaches out a finger to trace the darkest of the scars, starting at Sherlock’s right shoulder and crossing down, ending just above his top left rib. He stops just short when he realises what he is about to do.

“Sherlock?”

“Ah, John, there you are. I am at a very delicate point in this experiment, would you pass me that slide?” Sherlock keeps his eyes locked on the microscope, pointing at a slide sitting on the table.

“Er, Yeah. Of course, but, Sherlock?”

“John, what is it? I can’t take my eyes off this, I am waiting for it to hatch!”

“Oh. Ok, I was just wondering … Well, why are you not wearing a shirt?”

“Really, John. Is that the only question  you can think of? Not, ‘Oh Sherlock, is this for a case?’ Not, ‘hatch, you say, what is going to hatch?’ Nooo, you just go straight for the glaringly obvious. If you must know, Rosie splashed me while I was bathing her. I checked my experiment’s progress as I was on my way to change and things have reached a crucial stage. Now, if it is not too much trouble, would you  _ please _ pass me that slide before two weeks work is wasted!”

John does as he is told. “It’s just, well, you’ve been getting into a few-” Just as John drops the prepared glass slide into his outstretched hand, Sherlock moves. The slide falls to the table and shatters, razor-sharp shards flying in all directions. 

“Shit, Sherlock! I’m so sorry, I don’t know-” John stops abruptly; there is a three inch slice in Sherlock’s abdomen with blood dripping down to his naval. Half an inch above that is a large splinter of serrated glass, half embedded into Sherlock’s abdomen. Sherlock’s hands are hovering in mid-air as he first gazes down at his stomach and then back at John, helplessness filling his eyes.

“Oh, God, we need to get that out.” John steadies himself. “Right. I need more light.” John scans the kitchen before stepping through the arch into the living room, then once more back to Sherlock.

“Over to the sofa. I can use the lamp. Slowly,” he barks at Sherlock, who is cautiously standing up in an effort not to move the splinter.

With John guiding him and taking small, precise steps, Sherlock gets to the sofa and gingerly sits down. John grabs his first aid kit and a pair of tweezers from the bathroom. The bleeding from the cut has slowed, but John still hands Sherlock a large piece of gauze and orders him to press it firmly onto the wound. He angles the lamp so he can better see what he is doing, and then drops to the floor, kneeling between Sherlock’s legs so he can reach the splinter.

John is about to pass comment on the ridiculousness of their situation, on how Sherlock is hurt, yet again, from one of his bloody experiments. He calculates when the knife accident had been. Exactly a week ago, he realises, and the incident with the allergic reaction had been the week before that. He leans forward, so close that John is resting his elbows on the top of Sherlock’s thighs to steady his hands. As he reaches for the splinter with the tweezers, his mind volunteers the fact that the first accident, the burnt eyebrow, had also been on a Tuesday. Also at 7.30 p.m. 

Suddenly, as John leans so close to Sherlock that he can feel the other man’s balls pressing into his own chest, it all falls into place. Sherlock forgets, or more likely dismisses, the fact that John is also a man of science. John also understands the need to repeat an experiment in order to verify the results. He also knows that for the results to be comparable, the experiments must be conducted under the same conditions. In the same flat, for example. On the same night of the week, exactly one week apart, for example. At exactly 7.30 p.m. Sherlock has been conducting an experiment, all right. With John as its subject.

Well.

Two can play at  _ that  _ game. 

John has formed a hypothesis of his own and he is going to test it.

He says nothing, but gently removes the glass splinter. He sluices out the resulting wound, in case of any remaining grains of glass or infection, and is fastidious in smoothing it with antibacterial cream. He finishes by covering it with gauze and tape. Then he checks the lower cut, satisfied that it does not need stitches. 

All the time he is ministering to Sherlock, John remains on his knees between Sherlock’s legs. He murmurs words of encouragement. “Yes, hold that there. Perfect. No, don’t try to move just yet. Excellent. It must be very sore, you are doing very well, Sherlock. That’s it, we’re nearly done.” 

Sherlock is quiet and pliant, doing everything John tells him. When he is all finished, John closes up his first aid kit and leans forward. He closes his eyes and places a small, gentle kiss on Sherlock’s belly, just above the top wound. Then he gets to his feet and goes to the bathroom to put away his first aid kit. 

  
Sherlock says nothing. He sits on the sofa, staring at the mantelpiece for a few moments before collecting his laptop from the desk and disappearing into his room. Both men have an early night.


	5. Five Weeks back in 221b. Tuesday, 7.17 p.m.

**Summary for the Chapter:**

> Finally, an experiment goes very, very right.

 

John sits in his chair, drumming his fingertips on his thigh. Every now and again he becomes aware of what he is doing and stills his hand by clenching it into a fist. Then he realises again what he is doing and flexes the hand, forcing it to relax on his thigh. Moments later, the tapping resumes. 

He has spent the whole week vacillating back and forth over whether or not this is a good idea. Sometimes he is sure; he is confident of what Sherlock is doing and wants to know for certain, one way or another. If he is right, John is completely on board. 

He had tried, in his own inadequate, guilt and grief ridden way, to tell Sherlock he wanted this months earlier. He had come right out and told Sherlock he had wanted more - and still did. Then Sherlock had taken him in his arms and… well then, nothing. They had hugged and chatted and gone for cake. Then his mad sister had tried to kill them both in increasingly inventive ways. Taking their relationship further had been put on the back burner while they both focused on staying alive.

Now, here they are, settled. Content. Happy, and a family. John had not dared to raise the subject again. Not dared to rock the boat. Not dared to say that he wanted,  _ needed _ , to take that one tiny last step and belong to each other in every way possible; body, soul and heart. 

John already belonged to Sherlock. He had made that choice the day he and his daughter had left their old life behind and come home. For good. Forever. Whatever Sherlock wanted, John would give him. He had already committed his heart to trying to repay the debt he owed this man. The debt he owed for all the times Sherlock had lain down his own life for John. For all the times he had sacrificed his own happiness for John’s. The times John used him to absorb all his own pain, loss, anger and self-hatred, and Sherlock had allowed it.

Actions spoke louder than words, John believed. He would spend all the time he had left in this world showing Sherlock how very much he cared for him and repenting for his mistakes.

He had not expected to get the chance to show his feelings in a physical way. Now, a glimmer of hope had been ignited. Please, God, let him not have misread this situation. He has spent the other half of the week convincing himself that this is all in his imagination, that Sherlock does not, and never has, wanted him that way. 

Then, he changed his mind once more and believed that, in his own way and in his own time, Sherlock is again being the bravest of them both.

John has lusted after Sherlock for so long it has simply become part of his life. Clean your teeth, eat your toast, admire Sherlock’s cheekbones. Go to work, come home, stare at the man’s delectable arse. Sit in your chair, drink your tea, and force yourself to stay sitting and not reach over to the chair opposite and kiss that ridiculously beautiful mouth.

John glances again at his watch. 7:20. Ten more minutes and he will run his experiment and then he will know for certain, one way or another.

John hasn’t seen much of Sherlock today. There had been a late night call from Lestrade, an arrest made in the Belluci case. Sherlock had gone to ask the suspect some questions, leaving John at home with Rosie. He must have got in late, or at least gone to bed late, as he has been slow to surface.

On the kitchen table sits the equipment for Sherlock’s latest experiment, a complex series of glass flasks, tubes and bunsen burners. It gives John the heeby-jeebies to see it, a throwback to that awful time after Mary’s death.

No, John corrects himself. After you sent him away. 

The peace of the living room is disturbed by the rustling of a sheet declaring Sherlock’s arrival in the kitchen. John checks his watch again, 7.22. Bang on schedule. The kettle is filled and switched on.

“Good morning, sleeping beauty. Had a late one?”

Sherlock shuffles into the living room, gathering his sheet closely around him. His eyes scan the room.

“Yes, not in til four a.m., then I needed to think. Where is Rosie? Not in bed already? I set my alarm so I would not miss bathtime.”

“She’s with Mycroft.” John smiles at Sherlock’s horrified face.

“What, in God’s name, are you thinking, John? Mycroft doesn’t know the first  _ thing  _ about taking care of a child.” Sherlock starts to shuffle back towards the kitchen, travelling as fast as the tightly wound sheet will allow. Is he going to rescue her?John wonders.

“It’s fine. He hired not one, but two, nannies.”

Sherlock’s head snaps round. “How long is she staying there?” 

“Only until the morning,” John snorts. “I told him that as we’re family now, it was time he took his uncle responsibilities seriously, got to know Rosie a bit. I may have played slightly on the importance of family to him.” 

The last part was true but, in reality, John had claimed that he needed an uninterrupted evening with Sherlock to talk to him about his recent lack of coordination and becoming more accident prone. John had even hinted he would need to perform an examination, possibly a physical. He fervently hoped the latter would, at least, turn out to be true.

“And, of course, he responded with his usual panic and farming out of his responsibilities to paid underlings. His loss.” Sherlock sniffed.

While it was true that Mycroft had hired in staff just for 14 hours of child care, he was still a Holmes and had researched ways to entertain a 16-month old child. He had also shown a surprising interest in playing suitable games with Rosie while she stayed and the pitfalls of over-stimulation. John had a feeling that both parties would benefit from the brief sojourn. If things went well, it might be the beginning of a real family relationship. Rosie could do worse than to have Mycroft Holmes at her command.

“Did the kettle boil yet? I’ll join you in that tea.” John waited until Sherlock was in the kitchen before checking the time again. 7.28 p.m.

He waits for Sherlock to make the tea. As anxious as he was before, now that the moment is finally upon him, John is as calm as he would be in battle. He has a strategy and he is going to stick to it. 

John wanders into the kitchen and Sherlock hands him his tea. The microwave’s bright blue display shows it is exactly 7.30.

“How’s all that going? Your experiment?” John waves a hand at the contraption on the table. 

Sherlock is pouring a clear liquid in at one end, lighting a bunsen burner and setting it underneath a flask of clear liquid. In the next flask sits a red liquid. Both are connected to a condenser tube and a third flask. At the end, a pink liquid is slowly dripping into a collecting flask.

“Oh, good. Good.” Sherlock seems slightly flustered at John’s interest. He turns, and as he does so, the sheet falls looser and drops slightly from his shoulders. John’s heart rate picks up. This is exactly what he had been expecting to happen. Any minute now, Sherlock would ‘accidentally’ do something to hurt himself and John needed to step in before that happened yet again.

What he does is carefully place his mug on the counter and then slowly sink to his knees in front of Sherlock. He looks up, meeting a pair of astonished, wide, blue-grey eyes. Not looking away, he slides his hands inside the sheet and up Sherlock’s legs. He sweeps them up over the front of Sherlock’s thighs and brings them to a rest on his hips.

Sherlock just stares down at him. John grins naughtily and lifts his hands, opening up the front of the sheet.

“You know, you don’t have to hurt yourself for me to kiss you. That  _ is _ what you were going to do, isn’t it Sherlock? You were going to splash yourself with whatever is in that flask, I was going to patch you up and then kiss you better?”

Sherlock, apparently incapable of speech, simply nods his head slightly, eyes still locked on John’s face.

“Well, if you’re sure, then I think we can skip the accident part and jump straight to the kissing. If you are absolutely sure that is what you want? You know,” John takes a deep breath and pushes down the voice insisting he stop, shut up,  “you didn’t have to take all these risks. All you have ever,  _ ever _ had to do, was ask.”

Sherlock finally breathes out, the air escaping in a little mew. He lets the sheet drop to the floor and John finds himself only inches away from the most beautiful erection he has ever seen in his life.

“Please, John,” Sherlock breathes.

John is tempted to lean forward and take Sherlock in his mouth, whole, and to suck hard until Sherlock’s knees buckle. It takes a considerable amount of self control not to, but that is not how this should be. Instead, he stands and slides his hands around Sherlock’s naked waist and pulls him close. 

“You have been experimenting on me, haven’t you?”

Sherlock gives the tiniest of nods and John sees the fear clouding his eyes. Oh, God, he thinks I’m just calling his bluff.

Then John stops thinking. He slides his hands up Sherlock’s back and pulls him as close as possible, at the same time brushing his lips over Sherlock’s, rubbing his bottom lip over Sherlock’s own plump lip.

Just for a microsecond, they both pause. They each acknowledge that this is it, the moment where it all tips and changes, veers away and comes back into sharp focus. This is the moment where life will never be the same again and each man knows it will definitely consume him and fears that it may destroy him, but every single cell of his being begs him to do it anyway.

They crash into each other, kissing hard and deep, Sherlock pushing John’s head back and wrapping his long fingers through his hair. They kiss; loud, sloppy, careless kisses, panting and grasping at each other.

“The sofa,” John pants.

“No.” Sherlock pulls away, his focus intense and his eyes dark. “Bed. I want you in my bed.”

John slides his hand into Sherlock’s and leads them into Sherlock’s bedroom.

“You seem to have me at a disadvantage.” Sherlock breathes into his ear. 

John wants to wait, wants to let Sherlock slowly undress him with lingering touches and delicate kisses, but this is not the time. He wants to let Sherlock undress him with nips and beautiful words, but not tonight. Soon, he will spend a full half an hour just removing Sherlock’s shirt, but this is not that time. He rapidly removes his own shirt, jeans and underwear as Sherlock watches intently.

John cannot take his eyes from Sherlock’s face. The flush of his cheeks and the need in his eyes is intoxicating. His mind flashes back to that moment in Sherrinford when he watched Sherlock, tortured and exposed, punching through the empty coffin. He had seen a similar desperation in those eyes that day, a terror tempered by courage and determination.

“I love you.” The words are out before John even realises he has thought them. “I love you, Sherlock. I love you.” 

Sherlock sits on the edge of the bed and holds out his hand. John joins him and straddles Sherlock’s lap, laying him back against the pillows. 

John buries his face in the crook of Sherlock’s neck, breathing in the scent of him, kissing and licking. It occurs to John that he has no idea of Sherlock’s experience, although so far he certainly seems to know what he is doing. 

Sherlock deduces the hesitation and pushes John back up to sitting. He takes John’s dick firmly in his hand and begins to stroke. 

“I am no virgin, John, despite what you may all think. It has been a while, admittedly, but I am sure it will come back to me.” 

John arches back, unable to answer, pleasure and need consuming all sensible thought. A deep craving rolls through him. He reaches behind himself and takes Sherlock’s hot, leaking erection in his own hand. Sherlock bucks up at the touch, growling and holds John’s balls in his other hand. Each strokes the other until John can bear it no longer. He pushes Sherlock’s hands away and lies down on top of Sherlock’s chest, kissing, licking and biting every inch he can reach in a fury of need. He aches with lust but this is something else, something new, underlying his physical need. 

He slides between Sherlock’s splayed, welcoming legs and buries his hands in Sherlock’s hair. The first touch of their cocks together makes Sherlock keen and John shout. They rock together, Sherlock reaching down and grabbing John’s arse, keeping him fixed in place. John is kissing Sherlock, hard and demanding. 

The feel of Sherlock underneath him is exquisite. The heat of his damp skin, the slide of his cock, but he wants something, needs…

Without warning, Sherlock wraps his arms tightly around John, pushes down with his foot and flips them over. His larger body pins John to the bed, his head thrown back as he arches into John, speeding up the pace, increasing the friction between them, reaching for his own pleasure.

And this is what John was craving. Sherlock, taking, pinning him down, needing and using him. 

John opens his eyes and gorges on the man above him; head thrown back, eyes screwed shut, mouth open, hips snapping urgently. Taking. Sherlock  opens his eyes and meets John’s gaze. John is lost. As his orgasm hits, he knows he is lost. He has opened the last door in his defenses to Sherlock and welcomed him in. It will be this for as long as Sherlock wants him and nothing more ever again.

“John, John.” Sherlock ruts fast into the warmth of John’s come and as his own orgasm floods through him, he leans into John’s neck and rasps “I love you.”

As they lay together, panting, there is a loud bang from the kitchen and the sound of glass cracking and splintering.

  
“Shit! The bunsen burner,” laughs John, burying his head in Sherlock’s shoulder.

**Notes for the Chapter:**

> You can now read about Rosie's stay with Mycroft in [Doing Better](http://archiveofourown.org/works/10679796)


	6. Wednesday Morning

**Summary for the Chapter:**

> Sherlock outlines his methodology and John concludes his experiment.

**Notes for the Chapter:**

> Here we are at the end of March and the end of the story. Thank you all for reading and your lovely comments. Now onto the April Sherlock Challenge.

Sherlock stretches in every direction, arms above his head, legs as wide as he can get them, the right one falling off the edge of the bed in the process. Most of him hurts. Some, in a good way; muscles with a very specific purpose that have not been used for a long time; his cock is slightly raw, his arse tender and he has a sore spot on his neck where he suspects John bit him.

Other parts are a bit tender too. The cuts on his stomach are still healing and his knuckles are tight from the new scar tissue. His eyebrow has grown back well but his bottom lip is surprisingly tender. That may be from biting it as he came a second time last night, though.

Next to him, John is rousing, probably because Sherlock kicked him as he stretched. That may not have been an accident. A lot of things Sherlock has done recently may not have been altogether accidental.

Rolling onto his left side he props his head up on his hand as he closely examines John; sleepy eyes, hair sticking up in all directions, crumpled face and, he drops his hand over the top of the blanket to check, an impressive morning erection. Good.

“Good morning.” John smiles up at him and covers Sherlock’s hand with his own, pressing down and rolling his hips up in greeting.

“Good morning, John.” Sherlock growls, deciding right that second that he would like to wake up this way every single morning for the rest of his life. It was even good enough to bother going to sleep in the first place for.

“Well, that was…” John attempts.

“Yes. It was, rather.” They gaze at each other solemnly before laughing. Sherlock flops onto his back again.

John slides a hand under the blanket and over Sherlock’s chest, fingertips gliding lightly over the individual ribs, the curve at the bottom of each pectoral muscle, the lines of his clavicle, up over the top of each shoulder. It’s like John is trying to draw him.

“I’m sorry for spoiling your experiment.” John begins, quietly, “I just couldn’t take the risk of you hurting yourself again.”

Sherlock looks up into his serious face. “When did you work it out?”

“I think I had an idea when I kissed your finger better and you didn’t pull away or say anything. Then, the next week, with the slide, I felt awful. I really am sorry for breaking it like that. I couldn’t help myself, I had to kiss you better.”

“I had to stay on the sofa after you did. I was so hard, I couldn’t move. If you hadn’t got off me when you did…”

“I would have unzipped your trousers and taken you in my mouth.”

Sherlock’s eyes cloud over for a moment. John carries on with his exploratory stroking, index finger tracing Sherlock’s jawline, cheekbones, eye sockets. Sherlock closes his eyes and relaxes into his touch, trying to decide whether he should say something or not. Too often he opens his mouth and makes things worse, far worse. Was this going to be one of those occasions? Would John be angry that he had lied to him? More to the point, how angry would John be?

Sherlock sighed. _This_ was why he had never attempted this before. His feelings for John have been unwavering for years but he had long ago decided that it was better to love John from afar and keep him in his life than to act on it. It is better to have John’s friendship than to ignite what they have and then stand back and watch it torch them both alive.

“Do you like that, love?” John interprets the sigh as one of pleasure, and continues to explore Sherlock’s singular bone structure as he gazes down adoringly at the man.

Love. Maybe he should just get it over and done with and tell John the truth. Better to end things now before he gets used to this touch, these beautiful words. John has every right to be angry. Sherlock has manipulated him. He opens his eyes.

“It was not your fault that the slide broke, John.”

“Hmmmm?” John is more interested in stroking Sherlock’s left ear. Sherlock catches him by the wrist and steadies John’s hand, placing it on Sherlock’s chest and holding it there with his own.

“The slide, John. I intended it to break. I had scored it in a number of different directions then covered it with a fake sample. I deliberately moved my hand away as you passed it to me so it would fall and smash. I had predicted the pieces would travel in nine possible directions and had my torso positioned for maximum exposure and, therefore, damage. It was my fault. Not yours.”

John’s dark blue eyes flash. He stares down at Sherlock. For a moment, no one moves.

John leans down and kisses the end of Sherlock’s nose. “I know that, you berk. Well, I worked it out eventually. I saw the patterns; Rosie’s bedtime, always being back in the flat. _Tuesdays._ ”

“I may not have always been as hurt as I led you to believe.”

This gets John’s attention. He pulls his hand away and sits up, legs crossed under the sheets, frowning down at Sherlock.

“Go on, tell me the whole lot of it. The burn?”

“No actual explosion. Just a match near my eyebrow. I had vaseline on each side to stop it spreading.”

“Clever. Go on.”

“I generated the allergic reaction myself. It had nothing to do with the crime scene. I am allergic to a particular type of pollen so I bought a sample of it and rubbed it around the inside of my mouth and eyes.”

“No risk of poisoning then?”

“None. The anti-histamine tablet was sufficient. I also may have over-exaggerated the-”

“The lisping?”

“Yes.”

“Because you thought it was cute?”

Sherlock lowers his eyes. Yes, because he thought it may have a certain effect on John. He had deployed it with success on a number of cases.

“Well, I don’t know if ‘cute’ is the word I would use but-”

“Yeah, It was cute. Anymore? They say confession is good for the soul.”

“The cut with the knife. I had a-”  
  
“Blood capsule in your hand. Of course you did. I was surprised at the volume of blood and how quickly it healed. You prick.”

There it is. The name calling is back and the pretty words are gone. Sherlock closes his eyes, not able to watch John climb of of the bed and retreat away from him again.

“You manipulative, lying, gorgeous, bloody genius.”

Sherlock’s eyes fly open, ranging back and forth over the grinning John, who is lying back down next to him again.

“I have just one question, though.”

“Go on.”

“Why? Why did you do all this? The experiments gone wrong, the pain, the pretence? Why didn’t you just tell me you wanted this? Wanted me?”

The thought had never once crossed his mind. It had never occurred to him that John might sit down and have such a conversation. More to the point, how would he even begin to start to have that conversation himself? No, on balance, this had been easier. More his style. Not that he was about to admit that.

“Mycroft. It was all Mycroft’s fault. He called over one day when you were at work. I was taking care of Rosie and we were on the floor, playing with her bricks. He waltzed in, as he does, and demanded to be allowed to play too. I was horrified, but he just sat down with ‘well, you said they are family now so…’ Then he asked an interesting question.”

“Yeah? What?”  
  
“If John is your family, what am I to call him? Is he our brother now? Or is it more brother-in-law?”

“What did you say?”

“I didn’t say anything. Pompous arse was just trying to get a rise out of me, but I realised I didn’t know the answer and I hate not knowing so-”

“You decided to find out and, being a scientist, what else would you do except conduct experiments?”

“Exactly, John!” Sherlock forgets himself, delighted that John understands him so well.

“So, you devised a number of ways to hurt yourself, each escalating in severity to see how I would respond. You also made sure each experiment hurt a part of you lower and lower on your body.”

“Oh. You noticed that?”

“Yes, Sherlock. I noticed. I wasn’t sure if this was what you wanted exactly, but I am really, really over you hurting yourself to get my attention. Will you promise to stop now? Please?”

Sherlock considered that John had a point. It appears that John had meant it when he said he loved him. He is certainly taking all this far better than Sherlock had expected. If they were going to have a relationship, John may be inclined to kiss and stroke him without Sherlock being in pain first. The idea was very appealing. “I promise.”

“Good. Right, so we have Mycroft to thank for all this?”

“In part, I suppose.”

“Well, in that case, when I have finished _my_ latest experiment, I think we should pop over and collect Rosie and bring him a gift.”

“Experiment?”

“Yes. I intend to find out exactly what I need to do to you with my mouth to make you forget how to speak, because I am done with this conversation. Shall we proceed?”

Sherlock nods enthusiastically. He loves experiments.

**Notes for the Chapter:**

> Atlin Merrick has launched a 31 Day Porn Challenge for May 2017 and I am rising to that challenge. I shall be using the daily prompts to write Sherlock and John exploring this new relationship. Each story will be a stand alone work that forms part of this Series, Tuesdays and Thursdays, so please subscribe to the series, or me, if you want to find out how things develop. The works will be short to be able to keep up with the Challenge (although I am not promising to post every single day!)
> 
> I shall also be using some prompts to further develop Mycroft's story begun in Doing Better.


End file.
